Fast Live Cloning of Virtual Machine Based on Xen

Virtual machine (VM) cloning is to create a replica of a source virtual machine (parent virtual machine); the replica, also called child virtual machine, owns exactly the same executing status as parent virtual machine. Fast live cloning guarantees that, during the period of cloning, the services running on the parent virtual machine observe no performance degradation. There are three important goals for fast live cloning: reducing the total cloning time, minimizing the suspension time of the parent virtual machine, and maximizing resource sharing between the parent virtual machine and the child virtual machine. This paper exploits copy-on-write (CoW) mechanism fully to minimize the time of duplicating active main memory and secondary storage of the parent virtual machine. As a result, out experiments show that the total cloning time of a virtual machine on Xen virtual machine monitor can be confined within several hundred milliseconds and the downtime of parent virtual machine is limited to tens of milliseconds, close to VMMpsilas scheduling interval. Experiments also show that the parent virtual machine highly shares memory with the child virtual machine as long as both virtual machines continue executing the same applications.